Storage of ComputedStyle separate from LayoutObject.

third_party/WebKit/Source/core/dom/NodeRareData.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 16 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/dom/NodeRareData.h"
 
 #include "bindings/core/v8/ScriptWrappableVisitor.h"
 #include "core/dom/Element.h"
 #include "core/dom/ElementRareData.h"
 #include "core/frame/FrameHost.h"
+#include "core/layout/LayoutObject.h"

[Timothy Loh, 2016/06/23 23:58:02]

not needed?

 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 struct SameSizeAsNodeRareData {
     void* m_pointer;
     Member<void*> m_willbeMember[2];
     unsigned m_bitfields;
 };
 
 static_assert(sizeof(NodeRareData) == sizeof(SameSizeAsNodeRareData), "NodeRareData should stay small");
 
 DEFINE_TRACE_AFTER_DISPATCH(NodeRareData)
 {
     visitor->trace(m_mutationObserverData);
     // Do not keep empty NodeListsNodeData objects around.
     if (m_nodeLists && m_nodeLists->isEmpty())
         m_nodeLists.clear();
     else
         visitor->trace(m_nodeLists);
 }
 
 DEFINE_TRACE(NodeRareData)
 {
-    if (m_isElementRareData)
+    if (isElementRareData())
         static_cast<ElementRareData*>(this)->traceAfterDispatch(visitor);
     else
         traceAfterDispatch(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS(NodeRareData)
 {
-    if (m_isElementRareData)
+    if (isElementRareData())
         static_cast<const ElementRareData*>(this)->traceWrappersAfterDispatch(visitor);
     else
         traceWrappersAfterDispatch(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS_AFTER_DISPATCH(NodeRareData)
 {
     visitor->traceWrappers(m_nodeLists);
     visitor->traceWrappers(m_mutationObserverData);
 }
 
 void NodeRareData::finalizeGarbageCollectedObject()
 {
     RELEASE_ASSERT(!layoutObject());
-    if (m_isElementRareData)
+    if (isElementRareData())
         static_cast<ElementRareData*>(this)->~ElementRareData();
     else
         this->~NodeRareData();
 }
 
 void NodeRareData::incrementConnectedSubframeCount()
 {
     SECURITY_CHECK((m_connectedFrameCount + 1) <= FrameHost::maxNumberOfFrames);
     ++m_connectedFrameCount;
 }
 
 // Ensure the 10 bits reserved for the m_connectedFrameCount cannot overflow
 static_assert(FrameHost::maxNumberOfFrames < (1 << NodeRareData::ConnectedFrameCountBits), "Frame limit should fit in rare data count");
 
 } // namespace blink